Synthesis of Liquid-Crystalline Colloids in Nonpolar Media and their Manipulation in Electric Fields

摘要

The first synthesis of anisotropic liquid-crystalline colloids in silicone oil by a direct (radical) polymerization of a monomer in THF/silicone oil mixtures with the help of siloxane containing stabilizers is described. The size of the colloids is in the lower mu m range and can be adjusted by varying the mixture. The resulting colloids show a bipolar director configuration if they are small (<1.5 mu m) and a radial configuration if they are larger. The colloids are sterically stabilized, and, due to the nonpolarity of the solvent, the disturbing effects of migrating ions are excluded and experiments in the electric field can be conducted. Both line formation in DC fields and a periodic switching of the bipolar colloids in AC fields is observed.